Learn how to write Chinese by watching animations that draw
Chinese characters stroke by stroke (in simplified form as
used in mainland China). Subsections include
Surnames (with audio pronunciation),
Numbers,
the Chinese Zodiac, and more! You can also see the animated stroke orders by searching for characters by copying and pasting Simplified Chinese text.

New!
Input (copy-and-paste) any Chinese text and obtain the transliteration in Mandarin (pinyin) and hear audio clips of the pronunciation. Use this application to lookup pronunciations of unfamiliar words.

Other helpful sites:

Adsotrans
Copy and paste some text into Adsotrans and have it marked up with smart annotations (pinyin and English translations). Very useful site! See it in action at NewsInChinese. You can also contribute back to the project and increase the quality of the site by submitting your own translations and annotations.

Chinese-Course.com
Build your Chinese written and spoken vocabulary with character and sentence flashcards. This site uses the character data from the Ocrat Mirror project.

Zhongwen.com
Learn Chinese characters by studying how they are interrelated and
how they have evolved.

Pocket Chinese
Pocket Chinese is a free program for learning Chinese on your mobile phone.
The software lets you complete quizzes, hear pronunciations, and learn characters (including stroke order animations from this site).

On-line Chinese Tools
Looking for other Chinese-related web applications?
Here is a collection of interesting pages with a focus on Java.